Robert Heimer

Diarrheagenic Escherichia coli Infection in Baltimore, Maryland, and New Haven, Connecticut

BACKGROUND Diarrhea remains a common complaint among US patients who seek medical attention. METHODS We performed a prospective study to determine the etiology of diarrheal illness among patients and control subjects of all ages presenting to the emergency departments and outpatient clinics of 2 large academic hospitals in Baltimore, Maryland, and New Haven, Connecticut. We used molecular methods to detect the presence of diarrheagenic Escherichia coli pathotypes, including enteroaggregative E. coli (EAEC), as well as Shiga toxin-producing, cytodetaching, enterotoxigenic and enteropathogenic E. coli. RESULTS Of the pathotypes sought, only EAEC was found in an appreciable proportion (4.5%) of case patients, and it was found more frequently among case patients than control subjects (P<.02). Surprisingly, EAEC was the most common bacterial cause of diarrhea in our population. EAEC was common in all age strata and was not associated with foreign travel or immunodeficiency. EAEC infection is frequently accompanied by fever and abdominal pain, though this did not happen more frequently in patients with EAEC infection than in patients with diarrhea due to other causes. CONCLUSIONS Our data suggest that EAEC infection should be considered among persons with diarrhea that does not yield another known etiologic agent.

Transmission of HIV-1 infection in sub-Saharan Africa and effect of elimination of unsafe injections

During the past year, a group has argued that unsafe injections are a major if not the main mode of HIV-1 transmission in sub-Saharan Africa. We review the main arguments used to question the epidemiological interpretations on the lead role of unsafe sex in HIV-1 transmission, and conclude there is no compelling evidence that unsafe injections are a predominant mode of HIV-1 transmission in sub-Saharan Africa. Conversely, though there is a clear need to eliminate all unsafe injections, epidemiological evidence indicates that sexual transmission continues to be by far the major mode of spread of HIV-1 in the region. Increased efforts are needed to reduce sexual transmission of HIV-1.

Survival of Hepatitis C Virus in Syringes: Implication for Transmission among Injection Drug Users

BACKGROUND We hypothesized that the high prevalence of hepatitis C virus (HCV) among injection drug users might be due to prolonged virus survival in contaminated syringes. METHODS We developed a microculture assay to examine the viability of HCV. Syringes were loaded with blood spiked with HCV reporter virus (Jc1/GLuc2A) to simulate 2 scenarios of residual volumes: low void volume (2 microL) for 1-mL insulin syringes and high void volume (32 microL) for 1-mL tuberculin syringes. Syringes were stored at 4 degrees C, 22 degrees C, and 37 degrees C for up to 63 days before testing for HCV infectivity by using luciferase activity. RESULTS The virus decay rate was biphasic (t1/2alpha= 0.4 h and t1/2beta = 28 hh). Insulin syringes failed to yield viable HCV beyond day 1 at all storage temperatures except 4 degrees , in which 5% of syringes yielded viable virus on day 7. Tuberculin syringes yielded viable virus from 96%, 71%, and 52% of syringes after storage at 4 degrees, 22 degrees, and 37 degrees for 7 days, respectively, and yielded viable virus up to day 63. CONCLUSIONS The high prevalence of HCV among injection drug users may be partly due to the resilience of the virus and the syringe type. Our findings may be used to guide prevention strategies.

survival of Hiv-1 in Syringes

We performed a study to determine the duration of survival of HIV-1 in syringes typically used by injectors of illicit drugs (IDUs). We describe the effectiveness of a microculture assay in detecting viable virus in volumes of blood typical of those commonly found inside used syringes. Using this assay and modeling the worse-case situation for syringe sharing, we have recovered viable, proliferating HIV-1 from syringes that have been maintained at room temperature for periods in excess of 4 weeks. The percentage of syringes with viable virus varied with the volume of residual blood and the titer of HIV-1 in the blood. These experiments provide a scientific basis for needle exchange schemes, harm reduction, and other interventions among IDUs that support the nonsharing and removal of used syringes from circulation.

Can Syringe Exchange Serve as a Conduit to Substance Abuse Treatment

To determine how the city-run New Haven syringe exchange program (SEP) expedited requests, for entry into treatment, records of the SEPs drug treatment coordinator were analyzed. During the study period, a majority of those requesting treatment did not use the SEP to obtain sterile syringes. Comparisons between the people requesting treatment and those exchanging syringes revealed that those requesting treatment were more likely female and less like White. Factors associated with failure to enter treatment included long lag times, worse insurance, cocaine use, and requesting primary detoxification only. Majorities of the requests, appointments, and entries came from individuals whose treatment was to be paid through city welfare. A managed care initiative from the city welfare department, which excluded the SEP, halved requests or entries. Subsequent addition of the SEP to the initiative did not significantly increase requests or entries. Although the SEP initially acted as a conduit to treatment its effectiveness was curtailed by the imposition of bureaucratic restrictions.

Syringe use and reuse: effects of syringe exchange programs in four cities.

We determined the effect of syringe exchange programs (SEPs) on syringe reuse patterns. Five methods were employed to estimate injections per syringe made by exchange clients in four cities. In San Francisco, Chicago, and Baltimore, self-reported data on the number of injections per syringe were obtained. In New Haven, self-reported injection frequencies were combined with syringe tracking data to derive two methods for estimating the mean injections per syringe. The average number of injections per syringe declined by at least half after establishment of SEPs in New Haven, Baltimore, and Chicago, all cities where such an analysis could be made. There were significant increases in the percentages of exchangers reporting once-only use of their syringes in San Francisco, Baltimore, and Chicago, all cities where the data were amenable to this form of analysis. Self-report and syringe tracking estimates were in agreement that SEP participation was associated with decreases in syringe reuse by drug injectors. SEP participation was associated with increases in the once-only use of syringes. These findings add to earlier studies supporting the role of SEPs in reducing the transmission of syringe-borne infections such as HIV and hepatitis.

Needle exchange decreases the prevalence of HIV-1 proviral DNA in returned syringes in New Haven, Connecticut

PURPOSE To report on the deployment of the syringe tracking and testing system in the New Haven needle exchange program, which is the first federally funded evaluation of a needle exchange program conducted in the United States. PATIENTS AND METHODS A legal needle exchange for intravenous drug users began in New Haven, Connecticut, in November 1990. All syringes distributed by the program received unique tracking codes. Syringes were tracked and HIV-1 proviral DNA prevalence in returned syringes was assessed using polymerase chain reaction and Southern blotting. RESULTS At the outset of the program, the prevalence of HIV-1 proviral DNA in syringes exceeded two thirds. Prevalence decreased rapidly to less than 45% during the first 3 months of the program and remained at this level for the following 10 months. During the periods of decreasing prevalence and subsequent steady state, no changes in the demographics of program participants or in the drug use habits of newly enrolling clients that could account for the decrease in HIV-1 prevalence in needles were detected. In addition, the program referred almost 20% of its clients to drug treatment programs. CONCLUSION The needle exchange program in New Haven has decreased the percentage of syringes testing positive for HIV-1 proviral DNA among needle exchange clients while simultaneously serving as an entry point for drug treatment.

Critical Issues and Further Questions About Respondent-Driven Sampling: Comment on Ramirez-Valles, et al. (2005)

The application of respondent-driven sampling (RDS) is a promising new approach to understanding hidden populations, including those at high risk for HIV infection. The method has significant advantages over other sampling methods, including the possibility that representativeness samples can be accrued. However, the requirements for a respondent-driven sample to achieve representative and to demonstrate its superiority over other methods are quite strict. This report focuses on whether the accompanying paper by Ramirez-Valles et al. fulfills these requirements in terms of the theorems underlying RDS regarding sample recruitment rates, referral patterns, and network sizes. Further, it investigates the assertion that the accrued sample has proven that RDS is superior to more traditional time-location or venue-based sampling methods. Unconvinced that either is the case, the author suggests a method to test if RDS is indeed the gold-standard recruitment strategy for obtaining inclusive and representative samples of hidden populations.

Police Training to Align Law Enforcement and HIV Prevention: Preliminary Evidence From the Field

Having identified gaps in implementation of Rhode Islands syringe access law and police occupational safety education, public health and police professionals developed police training to boost legal knowledge, improve syringe access attitudes, and address needlestick injuries. Baseline data (94 officers) confirmed anxiety about needlestick injuries, poor legal knowledge, and occupational risk overestimation. Before training, respondents believed that syringe access promotes drug use (51%), increases likelihood of police needlestick injuries (58%), and fails to reduce epidemics (38%). Pretraining to posttraining evaluation suggested significant shifts in legal and occupational safety knowledge; changes in attitudes toward syringe access were promising. Training that combines occupational safety with syringe access content can help align law enforcement with public health goals. Additional research is needed to assess street-level effect and to inform intervention tailoring.

Patterns of drug use and abuse among aging adults with and without HIV: A latent class analysis of a US Veteran cohort

This study characterized the extent and patterns of self-reported drug use among aging adults with and without HIV, assessed differences in patterns by HIV status, and examined pattern correlates. Data derived from 6351 HIV-infected and uninfected adults enrolled in an eight-site matched cohort, the Veterans Aging Cohort Study (VACS). Using clinical variables from electronic medical records and socio-demographics, drug use consequences, and frequency of drug use from baseline surveys, we performed latent class analyses (LCA) stratified by HIV status and adjusted for clinical and socio-demographic covariates. Participants were, on average, age 50 (range 22-86), primarily male (95%) and African-American (64%). Five distinct patterns emerged: non-users, past primarily marijuana users, past multidrug users, current high consequence multidrug users, and current low consequence primarily marijuana users. HIV status strongly influenced class membership. Non-users were most prevalent among HIV uninfected (36.4%) and current high consequence multidrug users (25.5%) were most prevalent among HIV-infected. While problems of obesity marked those not currently using drugs, current users experienced higher prevalences of medical or mental health disorders. Multimorbidity was highest among past and current multidrug users. HIV-infected participants were more likely than HIV-uninfected participants to be current low consequence primarily marijuana users. In this sample, active drug use and abuse were common. HIV-infected and uninfected Veterans differed on extent and patterns of drug use and on important characteristics within identified classes. Findings have the potential to inform screening and intervention efforts in aging drug users with and without HIV.